She watched a group of ducks ride the swift current late Thursday evening and then awoke Friday to the sound of her sump pump. A portion of her basement was covered with river water, and the chair and table in her back yard were half-submerged.

“It’s coming from the walls, you see,” she said, pointing to a dark corner of her basement. “I knew living here what to expect, so it is not a total surprise.”

Chad Callahan, who in 2000 built a sprawling two-story home at the farthest end of River Street, didn’t sound worried. He had to take a canoe to his home in 2009, when the river came within a foot of the floorboards even though the house sits on special piers.

Natick Police are monitoring the situation on River Street, said Lieutenant Brian Grassey. “I did receive the Homeland Security prompt as well as [the Massachusetts Emergency Management Agency’s] prompt about flooding,” Grassey said, referring to flooding advisories from those two governmental agencies.

“We’re aware. I don’t think that today’s event, at this point is that serious, not any worse than we’ve anticipated.”

The National Weather Service issued flood warnings today for areas along the Charles, Sudbury, and Assabet rivers. The service issued a flood watch for areas across much of Eastern Massachusetts.

The service said residents living in flood-prone areas and along riverbanks should stay alert.

Flooding on the Charles in Natick area is common, according to the Natick Department of Public Works, and there’s no danger of any homes being swept away.

“We’re keeping our fingers crossed it doesn’t get worse — but we’re nervous,” said Bill Chenard, the department director. If things continue to escalate, Chenard said, the department is ready with sandbags and other assistance for residents.

In a span of 33 hours, roughly 1.5 to 3 inches of rain has fallen in Massachusetts. Royalston and Holliston have have so far seen the most rain, with 2.95 inches reported, followed by Hudson with 2.71 and Auburn with 2.7.

Already in June, 7.39 inches of rain has fallen, 5.5 inches more than normal for the entire month.

While rain was the problem inland, gusty northeast winds will pose problems for the east-facing shoreline. The weather service warned of high surf and potentially dangerous rip currents through Friday evening, with waters made choppy thanks to the strong winds. The service said the danger of rip currents could linger into Saturday.